1. Field of the Invention
This invention relates to a detection of voltage applied to a spark plug to detect faulty firing in an internal combustion engine.
2. Description of Prior Art
With the demand of purifying emission gas and enhancing fuel efficiency of internal combustion engine, it has been necessary to detect firing condition in each cylinder of the internal combustion engine so as to protect the internal combustion engine plug against misfire. In order to detect the firing condition in each of the cylinders, an optical sensor has been installed within the cylinders on one hand. On the other hand, a piezoelectrical sensor has been attached to a seat pad of the spark plug.
In those prior art counterparts, it is troublesome and time-consuming to install the sensor to each of the cylinders, thus increasing the installation cost, and at the same time, taking much time in check and maintenance.
Therefore, it is one of the objects of the invention to provide a sparkplug voltage probe device in an internal combustion engine which is capable of precisely detecting a voltage applied to the spark plug installed to each cylinder of the internal combustion engine with a relatively simple structure.